<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div>Cliff,</div><div>No worries, Hugh will have 2 subs to rescue me with by the time</div><div>mine is finished. The beauty of Hugh's regulator method is it</div><div>exhausts the overpressure, & a hole in the handle enables the system</div><div>to maintain your set pressure above ambient. I bought a cheap fibre reinforced plastic</div><div>regulator with the back pressure exhaust function for compensating,</div><div>but there were a few springs & bits that needed replacing with stainless.</div><div>Another option may be to oil compensate & use 1 regulator to pressurise</div><div>all motors. Just design it so that if the regulator or air lines failed, the compensating</div><div>oil wouldn't float out & would keep the motor pressurised at ambient.</div><div>Cheers Alan</div><div>Sent from my iPad</div><div><br>On 22/07/2014, at 5:40 am, Cliff Redus via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote:<br><br></div><blockquote type="cite"><div><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:12pt"><div><span></span></div><div></div><div>Alan I am glad your not advocating abandoning pressure compensation on your thrusters. I would sure hate to have to fly to New Zealand and rescue your skinny ass off the bottom near White Island!</div><div><br></div><div>If I use air to pressure compensate by MK-101's, I would use a variation of what Karl Stanley and Hugh Fulton are doing, i.e., use a scuba first stage regulator with the spring fully back out to get as close to ambient water pressure as I can but rather than letting air leak out the lip seal on ascent use an OTS ball style pressure relief valve with a 0.5 psi cracking pressure. Would need to play around with the amount of cracking pressure and the screw setting on the first stage to
make sure it vents through the valve and not the lip seal.</div><div><br></div><div>Agree, it would be good to get the Europeans experience on oil vs air pressure compensation of trolling motors.</div><div><br></div><div>Cliff<br><br><br></div><div><br></div><div><br></div> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 12pt;"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 12pt;"> <div dir="ltr"> <div class="hr" style="margin: 5px 0px; padding: 0px; border: 1px solid rgb(204, 204, 204); border-image: none; height: 0px; line-height: 0; font-size: 0px;" contenteditable="false" readonly="true"></div> <font face="Arial" size="2"> <b><span style="font-weight: bold;">From:</span></b> Alan via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>><br> <b><span style="font-weight: bold;">To:</span></b> Personal
Submersibles General Discussion <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> <br> <b><span style="font-weight: bold;">Sent:</span></b> Monday, July 21, 2014 11:08 AM<br> <b><span style="font-weight: bold;">Subject:</span></b> Re: [PSUBS-MAILIST] Minn Kota 101 - thread spec<br> </font> </div> <div class="y_msg_container"><br><div id="yiv7014649334"><div><div>Hi Cliff & all,</div><div>thanks for the expansion calculations Cliff. </div><div>I wasn't advocating using the 101s without compensation.</div><div>Just saying that they may not fail with the tube method because 3 out of 4</div><div>would operate down to 100ft with no compensation anyway.</div><div>Karl Stanley uses a first stage divers regulator with the spring removed to</div><div>give ambient air pressure to his motors; & just lets the over pressure on ascent</div><div>bubble out of the seals.</div><div> Hugh had the idea of using a pressure regulator that has back pressure
relief.</div><div>you just dial in an over-pressure of air to the motors. The stainless ones cost a couple of hundred each & you would probably need one on each motor + valves for each</div><div>to stem air flow if there was a failure.</div><div> Will try & dig up the negative comments on oil compensation made by the Europeans. </div><div>(when I wake up) Have them somewhere.</div><div>Regards Alan</div><div><br clear="none">Sent from my iPad</div><div><br clear="none">On 22/07/2014, at 2:22 am, Cliff Redus via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org" target="_blank" rel="nofollow" shape="rect" ymailto="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote:<br clear="none"><br clear="none"></div><blockquote type="cite"><div><div style="color: rgb(0, 0, 0); font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 12pt;
background-color: rgb(255, 255, 255);"><div id="yiv7014649334"><div><div style="color: rgb(0, 0, 0); font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 12pt; background-color: rgb(255, 255, 255);"><div id="yiv7014649334yui_3_16_0_7_1405949616767_4"><span></span></div><div id="yiv7014649334yui_3_16_0_7_1405949616767_5"></div><div> James, a couple of points. First, to me the fewer the leak paths the better so I would not install the added plug. The issue is how to get traped air out of the Md-101 when using oil compensation. I like Alec and Hanks ideas for removing trapped air due to nipple protruding into body. The other point is the wrap around tube volume can compensate for the small amount of air that remains trapped. To deal with thermal
expansion of the oil, first of all you are dealing with a small volume to start with so the tube/reservoir does not have to be all that large. If you do a quick back of the envelope calc on the required volume to compensate for only thermal expansion of the oil you about need 3 US teaspoons for a MK 101 ( Assume oil has a thermal expansion coefficient of 0.00056 1/F and that there is one US pint of oil in the body of the 101 and that the temperature swing is 70F to 130F. Delta volume is 0.125 gal * 0.00056 1/F * 60F = 0.0042 gal*128 OZ/gal *6 US TSP/OZ = 3.2 teaspoons). </div><div>To me the design pressure inside the ME 101 should be ambient pressure as they have lip seals on shafts. Lip seals are design to take external pressure. They re not designed to take internal pressure. So a simple wrap around tube for oil compensation with say a volume of 5 US teaspoons should work just fine as this would allow
for thermal expansion of the oil and a small volume of trapped air and because the tube is flexible, the pressure inside the 101 is ambient which makes the lip seal happy. As to Alan's suggestion on omitting all pressure compensation and only relaying on the lip seal without any pressure compensation, I am not wild about this idea unless the boat is only designed for shallow water. MK designers when they speced the lip seals for MK were designing shallow submergence of a trolling motor with a factor of safety. So as you get deeper and deeper, you are starting to expose these lips seals to a significant differential pressure which causes them to overheat and fail at some point. Is this 10ft or 50 ft or 100 ft. Don't know but to me this exposes the boat to some risk particularly if use the 101's for depth stability rather than a VBT and dive the boat negatively buoyant, i.e., vertical thruster fails,
boat starts to descend and pilot is forced into dropping ballast. </div><div><br clear="none"></div><div>To me a bigger question on air vs oil compensation is how much power are you giving up with oil compensation due to viscosity difference between oil and air. </div><div><br clear="none"></div><div>As both Alec and Vance point out, there has been a lot of bottom time on MD-101s with oil compensation without a lot documented failures. </div><div><br clear="none"></div><div>I have not decided in my own mind which compensation method I will use on my MD-101's for future boats. </div><div><br id="yiv7014649334yui_3_16_0_7_1405949616767_11" clear="none"></div><div id="yiv7014649334yui_3_16_0_7_1405949616767_12">Cliff</div><div><br id="yiv7014649334yui_3_16_0_7_1405949616767_15" clear="none"></div> <div class="yiv7014649334ms__id7917" id="yiv7014649334yui_3_16_0_7_1405949616767_17" style="font-family:
HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 12pt;"> <div class="yiv7014649334ms__id7918" style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 12pt;"> <div class="yiv7014649334qtdSeparateBR"><br clear="none"><br clear="none"></div><div class="yiv7014649334yqt3237743508" id="yiv7014649334yqt30031"><div dir="ltr"> <div class="yiv7014649334hr yiv7014649334yui-non yiv7014649334yui-skip" style="margin: 5px 0px; padding: 0px; border: 1px solid rgb(204, 204, 204); border-image: none; height: 0px; line-height: 0; font-size: 0px;"></div> <font face="Arial" size="2"> <b><span style="font-weight: bold;">From:</span></b> James Frankland via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org" target="_blank" rel="nofollow" shape="rect" ymailto="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>><br clear="none"> <b><span style="font-weight: bold;">To:</span></b> Personal Submersibles General Discussion <<a href="mailto:personal_submersibles@psubs.org" target="_blank" rel="nofollow" shape="rect" ymailto="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> <br clear="none"> <b><span style="font-weight: bold;">Sent:</span></b> Monday, July 21, 2014 4:17 AM<br clear="none"> <b><span style="font-weight: bold;">Subject:</span></b> Re: [PSUBS-MAILIST] Minn Kota 101 - thread spec<br clear="none"> </font> </div> <div class="yiv7014649334y_msg_container"><br clear="none"><div id="yiv7014649334"><div><div dir="ltr"><div>Hi Cliff,,</div><div>Others may disagree with this, but ive got a suggestion. If your oil compensating the motors and are going to add the wrap around tube\bladder as per Alecs Snoopy, I would suggest, adding a vent hole somewhere near the aft bearing. With my setup, ive put the tube going around
the motor and its all ok. But, I just cannot get the last dregs of air out. No matter what I do. I suspect that its because the pipe nipple protrudes a mm or so into the casing and so will not allow the last bit of air out. It really irritates me and I worry that the motor is not properly compensated. So, I am going
to make a modification to the motor like this pic. I think this will work, the suspect bit is mating the plug against the slightly domed motor case. I think a large
rubber washer should seal it. The i should be able to rotate the motor and remove the last dregs of air. What do you think?<br clear="none">
Thanks</div><div>James</div><div><div><motor.jpg><br clear="none"></div> </div></div><div class="yiv7014649334gmail_extra"><br clear="none"><br clear="none"><div class="yiv7014649334gmail_quote">On 19 July 2014 01:38, Clifford Redus via Personal_Submersibles <span dir="ltr"><<a href="mailto:personal_submersibles@psubs.org" target="_blank" rel="nofollow" shape="rect" ymailto="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>></span> wrote:<br clear="none">
<blockquote class="yiv7014649334gmail_quote" style="margin: 0px 0px 0px 0.8ex; padding-left: 1ex; border-left-color: rgb(204, 204, 204); border-left-width: 1px; border-left-style: solid;"><div class="yiv7014649334yqt9652392429" id="yiv7014649334yqt88107"><div><div>Thanks<span class="yiv7014649334HOEnZb"><font color="#888888"><br clear="none"><br clear="none"><br clear="none"></font></span><div>Cliff Redus</div></div>
<div><div class="yiv7014649334h5"><div><br clear="none">On Jul 18, 2014, at 7:26 PM, Alec Smyth via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org" target="_blank" rel="nofollow" shape="rect" ymailto="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote:<br clear="none"><br clear="none"></div>
<blockquote type="cite"><div><div dir="ltr">Hi Cliff,<div><br clear="none"></div><div>It is a parallel thread, 1 1/8" - 18.</div><div><br clear="none"></div><div>Best,</div><div><br clear="none"></div><div>Alec</div></div><div class="yiv7014649334gmail_extra"><br clear="none"><br clear="none">
<div class="yiv7014649334gmail_quote">On Fri, Jul 18, 2014 at 8:04 PM, Cliff Redus via Personal_Submersibles <span dir="ltr"><<a href="mailto:personal_submersibles@psubs.org" target="_blank" rel="nofollow" shape="rect" ymailto="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>></span> wrote:<br clear="none">
<blockquote class="yiv7014649334gmail_quote" style="margin: 0px 0px 0px 0.8ex; padding-left: 1ex; border-left-color: rgb(204, 204, 204); border-left-width: 1px; border-left-style: solid;"><div><div class="yiv7014649334ms__id7926" style="color: rgb(0, 0, 0); font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 12pt; background-color: rgb(255, 255, 255);">
<div><span></span></div><div></div><div> Does anyone have any documentation on the Minn Kota 101 main support female thread spec? It does not look like a tapered pipe thread and the threads per inch look to great. I put a digital caliper on this at it read 1.064-1.07 inches for the minor diameter. I measured the threads and it is 18 threads per inch. I looked in the machine handbook and the closest that comes is a 1-1/8 UNEF (Extra fine thread series). The major and minor diameters for a 1-1/8" UNEF are 1.1250" and 1.0649" respectively.</div>
<div><br clear="none"></div><div>Can anyone confirm this?</div><span><font color="#888888"></font></span><div><br clear="none"></div><div>Cliff<br clear="none"></div> </div></div><br clear="none">_______________________________________________<br clear="none">
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